It seems that custom shape map and custom theme are not taken into account once published.
With shape map when the report is edited in the service, the json file configuration is not visible.
Currently power bi doesn't support let user edit the configuration of custom shape map. You should modify the settings in power bi desktop side. In addtion, you can also submit your idea here to help power bi improve.
issue is closed! it was due to our company security team who implémented new security actions in our network with our proxies.
All Power BI internet data was decrypted for antivirus analysis.
It caused slowness in all our reports and issues with themes and visuals using json.
So if you are experiencing slowness and wierd behaviour that is not reported in the community, do not forget to ask your network team if they changed something.
Thanks for sharing your solution.